/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 26727
 * Date: 2024-08-31
 * Time: 20:41
 */
public class Test {
    public static void main(String[] args) {
        int n = 101;
        int cnt = 0;
        for(int i = 1; i <= n; i++) {
            for(int j = i; j <= n; j++) {
                cnt  = cnt+1;
            }
        }
        System.out.println(cnt);
    }
}
